Information processing applications must often find a value within a range of values. For example, a sorting system may organize discrete units of information into groups defined by numerical boundaries. Before assigning each discrete unit of information to a group, the relationship between each discrete unit of information and the numerical boundaries must be established. Defining these relationships often requires finding a value within a range of values. In some sorting systems, this is accomplished using a compute intensive sort algorithm in combination with a high performance microprocessor. Unfortunately, high performance microprocessors are expensive, and therefore not suitable for use in products directed to the consumer market.
An analog-to-digital (A/D) converter generates digital output information related to analog input information. The conversion process associated with one type of A/D converter requires manipulating discrete pieces of information, the on and off states of resistor ladder switches, in such a way that the final configuration of resistor ladder switches matches a value within a range of values. Modem A/D converters are designed to operate on a single chip and to function in a variety of end user applications, such as cellular telephones and video games. A single A/D converter design may be required to function in an application that requires eight, twelve, sixteen or more bits of resolution. Designers attempt to provide this flexibility in an A/D converter by providing an on chip microprocessor. Unfortunately, the supplied microprocessor often has a limited instruction set, and operates at a low frequency, so the requirements for applications that must operate at both high frequency and high resolution, such as quickly matching a two byte value within a range of values, are difficult to meet.
Some control systems seek to drive a difference signal, which is the difference between an output information signal and an input signal, to zero in order to maintain a constant relationship between the input signal and the output information signal. This process of driving the difference signal to zero may require the identification of a value within a range of values.
In modern digital control systems, the control function is often performed by a microprocessor. In some systems designed primarily for high reliability, such as systems designed for use in satellites, high function may also be required. High function microprocessors tend to fail more often than low function microprocessors, so it is difficult to meet both requirements, and often a low function microprocessor is selected for a particular application. Unfortunately, the same algorithms and software that accomplish tasks on a high function microprocessor, such as identifying a value within a range of values, do not work on low function microprocessors.
For these and other reasons there is a need for the present invention.